Files
semantic-kernel/python
Weiguang LiandEvan Mattson e500f727ed Python: fix prompt template engine blocking HTML tags in content (#13633)
### Motivation and Context

Fixes #13632

When a prompt contains HTML tags such as `<p>`, `<div>`, `<b>`, etc.,
the
`ChatHistory.from_rendered_prompt()` method wraps the rendered prompt in
a
`<root>` element and parses it as XML. Any child elements whose tag
names do
not match the known SK template tags (`message`, `chat_history`) were
silently
skipped, causing their text content to be lost. This meant a prompt
like:

```
Translate: "<p>What is your name?</p>"
```

would arrive at the LLM as an empty message, because `<p>What is your
name?</p>`
was discarded during XML traversal.

### Description

In `ChatHistory.from_rendered_prompt`, when an XML child element has an
unrecognized tag (i.e. it is not `message` or `chat_history`), the
element
is now serialized back to its original text representation and appended
to
the preceding message content. The element's tail text is likewise kept
in
the same message, preserving the full original prompt text.

**Changed files:**

- `python/semantic_kernel/contents/chat_history.py` -- handle unknown
XML
  tags as literal text in `from_rendered_prompt()`
- `python/tests/unit/contents/test_chat_history.py` -- added four
regression
tests covering HTML `<p>`, multiple HTML tags, HTML surrounded by text,
  and SK tags mixed with HTML

### Contribution Checklist

- [x] The code builds clean without any errors or warnings
- [x] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
- [x] The existing tests pass and new tests have been added
- [x] I didn't break any existing functionality

---------

Co-authored-by: Evan Mattson <[email protected]>
2026-03-18 11:01:25 +00:00
..
2023-04-13 16:12:36 -07:00
2024-08-27 16:45:09 +00:00

Get Started with Semantic Kernel Python

Highlights

  • Flexible Agent Framework: build, orchestrate, and deploy AI agents and multi-agent systems
  • Multi-Agent Systems: Model workflows and collaboration between AI specialists
  • Plugin Ecosystem: Extend with Python, OpenAPI, Model Context Protocol (MCP), and more
  • LLM Support: OpenAI, Azure OpenAI, Hugging Face, Mistral, Google AI, ONNX, Ollama, NVIDIA NIM, and others
  • Vector DB Support: Azure AI Search, Elasticsearch, Chroma, and more
  • Process Framework: Build structured business processes with workflow modeling
  • Multimodal: Text, vision, audio

Quick Install

pip install --upgrade semantic-kernel
# Optional: Add integrations
pip install --upgrade semantic-kernel[hugging_face]
pip install --upgrade semantic-kernel[all]

Supported Platforms:

  • Python: 3.10+
  • OS: Windows, macOS, Linux

1. Setup API Keys

Set as environment variables, or create a .env file at your project root:

OPENAI_API_KEY=sk-...
OPENAI_CHAT_MODEL_ID=...
...
AZURE_OPENAI_API_KEY=...
AZURE_OPENAI_ENDPOINT=...
AZURE_OPENAI_CHAT_DEPLOYMENT_NAME=...
...

You can also override environment variables by explicitly passing configuration parameters to the AI service constructor:

chat_service = AzureChatCompletion(
    api_key=...,
    endpoint=...,
    deployment_name=...,
    api_version=...,
)

See the following setup guide for more information.

2. Use the Kernel for Prompt Engineering

Create prompt functions and invoke them via the Kernel:

import asyncio
from semantic_kernel import Kernel
from semantic_kernel.connectors.ai.open_ai import OpenAIChatCompletion
from semantic_kernel.functions import KernelArguments

kernel = Kernel()
kernel.add_service(OpenAIChatCompletion())

prompt = """
1) A robot may not injure a human being...
2) A robot must obey orders given it by human beings...
3) A robot must protect its own existence...

Give me the TLDR in exactly {{$num_words}} words."""


async def main():
    result = await kernel.invoke_prompt(prompt, arguments=KernelArguments(num_words=5))
    print(result)


asyncio.run(main())
# Output: Protect humans, obey, self-preserve, prioritized.

3. Directly Use AI Services (No Kernel Required)

You can use the AI service classes directly for advanced workflows:

import asyncio
import asyncio

from semantic_kernel.connectors.ai.open_ai import OpenAIChatCompletion, OpenAIChatPromptExecutionSettings
from semantic_kernel.contents import ChatHistory


async def main():
    service = OpenAIChatCompletion()
    settings = OpenAIChatPromptExecutionSettings()

    chat_history = ChatHistory(system_message="You are a helpful assistant.")
    chat_history.add_user_message("Write a haiku about Semantic Kernel.")
    response = await service.get_chat_message_content(chat_history=chat_history, settings=settings)
    print(response.content)

    """
    Output:

    Thoughts weave through context,  
    Semantic threads interlace—  
    Kernel sparks meaning.
    """


asyncio.run(main())

4. Build an Agent with Plugins and Tools

Add Python functions as plugins or Pydantic models as structured outputs;

Enhance your agent with custom tools (plugins) and structured output:

import asyncio
from typing import Annotated
from pydantic import BaseModel
from semantic_kernel.agents import ChatCompletionAgent
from semantic_kernel.connectors.ai.open_ai import AzureChatCompletion, OpenAIChatPromptExecutionSettings
from semantic_kernel.functions import kernel_function, KernelArguments

class MenuPlugin:
    @kernel_function(description="Provides a list of specials from the menu.")
    def get_specials(self) -> Annotated[str, "Returns the specials from the menu."]:
        return """
        Special Soup: Clam Chowder
        Special Salad: Cobb Salad
        Special Drink: Chai Tea
        """

    @kernel_function(description="Provides the price of the requested menu item.")
    def get_item_price(
        self, menu_item: Annotated[str, "The name of the menu item."]
    ) -> Annotated[str, "Returns the price of the menu item."]:
        return "$9.99"

class MenuItem(BaseModel):
    # Used for structured outputs
    price: float
    name: str

async def main():
    # Configure structured outputs format
    settings = OpenAIChatPromptExecutionSettings()
    settings.response_format = MenuItem

    # Create agent with plugin and settings
    agent = ChatCompletionAgent(
        service=AzureChatCompletion(),
        name="SK-Assistant",
        instructions="You are a helpful assistant.",
        plugins=[MenuPlugin()],
        arguments=KernelArguments(settings)
    )

    response = await agent.get_response("What is the price of the soup special?")
    print(response.content)

    # Output:
    # The price of the Clam Chowder, which is the soup special, is $9.99.

asyncio.run(main()) 

You can explore additional getting started agent samples here.

5. Multi-Agent Orchestration

Coordinate a group of agents to iteratively solve a problem or refine content together:

import asyncio
from semantic_kernel.agents import ChatCompletionAgent, GroupChatOrchestration, RoundRobinGroupChatManager
from semantic_kernel.agents.runtime import InProcessRuntime
from semantic_kernel.connectors.ai.open_ai import AzureChatCompletion

def get_agents():
    return [
        ChatCompletionAgent(
            name="Writer",
            instructions="You are a creative content writer. Generate and refine slogans based on feedback.",
            service=AzureChatCompletion(),
        ),
        ChatCompletionAgent(
            name="Reviewer",
            instructions="You are a critical reviewer. Provide detailed feedback on proposed slogans.",
            service=AzureChatCompletion(),
        ),
    ]

async def main():
    agents = get_agents()
    group_chat = GroupChatOrchestration(
        members=agents,
        manager=RoundRobinGroupChatManager(max_rounds=5),
    )
    runtime = InProcessRuntime()
    runtime.start()
    result = await group_chat.invoke(
        task="Create a slogan for a new electric SUV that is affordable and fun to drive.",
        runtime=runtime,
    )
    value = await result.get()
    print(f"Final Slogan: {value}")

    # Example Output:
    # Final Slogan: "Feel the Charge: Adventure Meets Affordability in Your New Electric SUV!"

    await runtime.stop_when_idle()

if __name__ == "__main__":
    asyncio.run(main())

For orchestration-focused examples, see these orchestration samples.

More Examples & Notebooks

Semantic Kernel Documentation